1. Field of the Invention
The present invention is concerned generally with agricultural implements and more specifically to an improved apparatus and method for transferring agricultural seed or other particulate material from a principal storage site to individual material metering hoppers mounted on planters, grain drills and the like.
2. Background
In the past, distribution of seed (or other particulate material such as fertilizer) for use in a variety of agricultural operations has been effected with the use of a plurality of row dispensing bins each of which has an associated metering device for applying pre-selected quantities of the seed or other particulate material to the land. These individual bins generally had limited storage capacity, for example 1 to 3 bushels and therefore required frequent refilling, which filling, if is effected from a fixed storage tank site, increased the overall planting time. Subsequent in time, the "down" time that occurred because of the use of fixed site storage tanks was basically eliminated by the development of apparatus in which a central supply of material was carried on the mobile equipment so that the dispensing bins could be resupplied with material during operation in the field. A seed distribution system in which grain is conveyed from an equipment-mounted main hopper can be seen in U.S. Pat. No. 5,161,173 issued Nov. 10, 1992 and assigned to Deere and Company. This system utilizes a single main hopper which dispenses seed to a plurality of individual or mini-hoppers that each, in turn, supply seed to an individual planting row. The seed is fed from the main hopper into each mini-hopper by entraining it in an airstream contained in separate, individual transfer hoses that are connected between the main tank and each of the individual mini-hoppers.
U.S. Pat. No. 5,379,706, issued Jan. 10, 1995 and assigned to Agco Corporation, is illustrative of another seed transporting system which also utilizes a central storage hopper for supplying a plurality of smaller, satellite hoppers via a plurality of individual hoses or tubes running from the central hopper to each of the individual satellite, row hoppers. Thus, while the systems of the 'BM73 and '706 patents provide for the maintenance of seed supply quantities in the row hoppers during seeding operations, they also require the incorporation of a large number of separate seed transport tubes in those systems where multiple, mini-hoppers are present. Since the requirement that multiple, individual seed feeding tubes to supply the dispensing hoppers may involve higher initial equipment costs and also increased maintenance costs, a more efficacious system would be one where the seed supply tube from the main tank are kept to a minimum.